Grab device for timber



Jan. 3, 1967 K. E. WALLBERG GRAB DEVICE FOR TIMBER 5 Sheets-Sheet 1Filed March 1, 1965 w pmlam W Jan. 3, 1967 Filed March 1, 1965 K. E.WALLBERG GRAB DEVICE FOR TIMBER 5 Sheets-Sheet 2 QQmuQMZoL by w wzrew/ken. am

Jan. 3, 1967 K. E. WALLBERG GRAB DEVICE FOR TIMBER Filed March 1, 1965 3Sheets-Sheet 5 cirvwwlm we m wwuzw United States Patent Office 3,295,882Patented Jan. 3, 1967 3,295,882 GRAB DEVICE FGR TIMBER Karl ErikWallberg, Bergnaset, Sweden, assignor to Kewacos Forsaljningsaktiebolag,Lulea, Sweden Filed Mar. 1, 1965, Ser. No. 436,726 Claims priority,appiication Sweden, Mar. 3, 1964, 2,562/ 64 6 Claims. (Cl. 29488) Thepresent invention relates to a grab device for timber having asubstantially U-shaped fork and a grab clamp pivoted to the upper shankof the fork and a piston engine to actuate the grab clamp.

In such grab devices it is difiicult and often impossible when loadingtimber on transport vehicles or Working benches to maintain a single ora small number of logs in horizontal position, because the gap of thefork, as a rule, is dimensioned for taking up greater loads.

One purpose of the invention is to eliminate this disadvantage, andaccording to the invention this is brought about in such a way that forgrabbing a single or a small number of logs with a fork intended forgreater loads a clamping link is connected close to the attaching pointof the grab clamp so that when the grab clamp is brought into positionto close the fork, the clamping link is turned toward the grab clamp, itbeing possible thus to reduce the gap of the fork.

The clamping link is preferably adapted to be retractable into theU-shaped bend of the fork at rest. The clamping link is preferablyarranged to be actuated by the grab clamp only when the latter passeshalf of the fork depth. It is also suitable that the grab clamp and theclamping link are provided with cooperating ridges. To the free end ofthe clamping link a second link may be connected, the free end of which.runs in a guide attached to the fork. The clamping link is kept at restin the fork by means of a tension spring.

The invention will be further described in the following in connectionwith the accompanying drawing, where FIGURE 1 shows a vertical sideelevation of an embodiment of the grab device according to theinvention, FIG- URE 2 shows a vertical side elevation of a secondembodiment of the device, FIGURE 3 shows a part of the clamping link ofboth FIGS. 1 and 2 at rest and retracted into the fork and FIGURE 4shows a part of the clamping link of both FIGS. 1 and 2 and as actuatedby the grab clamp in clamping position.

According to FIGURE 1 a substantially U-shaped fork 1 is connected atthe pivot 8 with a grab clamp 2, which is actuated by means of a pistonengine 3. The grab clamp is provided with a ridge 4, which is arrangedto engage a second ridge 6 on the clamping link 5. The clamping link isattached at the pivot 7 to the upper shank end of the fork near thepivot 8 of the grab clamp 2. A second link 9 is pivoted to the free endof the clamping link 5 with its free end carried in a guide 10 on thefork. 11 is a tension spring, which is tensioned to move the clampinglink toward the fork and to keep the clamping link at rest retractedinto the U-shaped bend of the fork. 16 is a log, which is held betweenthe grab clamp 2 and the link 9 in horizontal position 12 and 13 arebrackets for securing the grab device to a support such as a truck whichis not shown.

In FIGURE 2 the fork 1 is similar to that shown in FIGURE 1 and is alsoprovided with a grab clamp 2 and a clamping link 5. The link 9' howeveris different from the link 9 shown in FIGURE 1 and provides greaterspace for grabbing timber than in the device according to FIG- URE l.The free end of the link d is furnished with a slot 14, in which a tap15 on the fork engages. In the retracted position of the clamping link 5the link 9 takes the position marked with dash and dot lines. Three logsclamped between the link 9 and the grab clamp 2 in horizontal positionare designated by 16. According to FIG- URE 3 the clamping link 5 is atrest and quite retracted in the fork 1, while the grab clamp 2 is in theinitial or open position and the piston rod 17 is drawn into thecylinder 18.

According to FIGURE 4 the ridge 4 of the grab clamp 2 has actuated theridge 6 of the clamping link 5 and turned the clamping link outwardstoward the grab clamp.

The device is of course not confined to the embodiments shown in thedrawing but may be altered within the scope of the invention as definedin the appended claims. Thus the clamping link may for instance beformed in one piece so that a log may be grabbed by the grab clamp andthe clamping link as by shears and in this way secured in horizontalposition.

I claim:

1. A grab device for timber comprising a substantially U-shaped forkwhich in its normal position has an upper and a lower arm and an openand a closed side, a first pivot adjacent to the free end of said upperarm, a grab clamp connected adjacent its upper end to said first pivot,a piston engine connected between said fork and said grab clamp andadapted to swing said grab clamp through said open side, a second pivoton the upper arm of said fork adjacent to said first pivot, a clampinglink connected adjacent to its upper end to said second pivot and meansconnecting said grab clamp and said clamping link whereby the free endof the latter is moved forwardly toward said open side when the free endof the former moves rearwardly through said open side into the spacebetween said upper and lower arms.

2. A grab device as defined in claim 1, comprising means tending to holdthe free end of said clamping link adjacent to said upper arm of saidfork.

3. A grab device as defined in claim 2, in which said means tending tohold the free end of said clamping link adjacet to said upper arm ofsaid fork is a spring.

4. A grab device as defined in claim 1, in which said means actuatessaid clamping link to move forwardly only when said grab clamp movesinwardly farther than half the depth of the space between said upper andlower arms.

5. A grab device as defined in claim 1, in which said means consists ofcooperating ridges adjacent the pivoted ends of said grab clamp and saidclamping link.

6. A grab device as defined in claim 1, comprising a third pivotadjacent to the free end of said clamping link, a second link connectedadjacent one end thereof to said third pivot and a guide on said forkfor the other end of said second link.

References Cited by the Examiner UNITED STATES PATENTS 3,119,637 1/1964Eaves 294104 X 3,165,345 1/1965 Gardner 294-104 X 3,165,348 1/1965Keski-talo 29488 3,194,421 7/1965 Lull 2 l4l47 FOREIGN PATENTS 25,4866/1952 Finland.

HUGO O. SCHULZ, Primary Examiner.

1. A GRAB DEVICE FOR TIMBER COMPRISING A SUBSTANTIALLY U-SHAPED FORKWHICH IN ITS NORMAL POSITION HAS AN UPPER AND A LOWER ARM AND AN OPENAND A CLOSED SIDE, A FIRST PIVOT ADJACENT TO THE FREE END OF SAID UPPERARM, A GRAB CLAMP CONNECTED ADJACENT ITS UPPER END TO SAID FIRST PIVOT,A PISTON ENGINE CONNECTED BETWEEN SAID FORK AND SAID GRAB CLAMP ANDADAPTED TO SWING SAID GRAB CLAMP THROUGH SAID OPEN SIDE, A SECOND PIVOTON THE UPPER ARM OF SAID FORK ADJACENT TO SAID FIRST PIVOT, A CLAMPINGLINK CONNECTED ADJACENT TO ITS UPPER END TO SAID SECOND PIVOT AND MEANSCONNECTING SAID GRAB CLAMP AND SAID CLAMPING LINK WHEREBY THE FREE ENDOF THE LATTER IS MOVED FORWARDLY TOWARD SAID OPEN SIDE WHEN THE FREE ENDOF THE FORMER MOVES REARWARDLY THROUGH SAID OPEN SIDE INTO THE SPACEBETWEEN SAID UPPER AND LOWER ARMS.